1. Field of the Invention
The subject invention generally pertains to heating, ventilating and air conditioning (HVAC) dampers and more specifically to an actuator for such a damper.
2. Description of Related Art
HVAC systems often include various dampers for controlling airflow through the system. The dampers typically comprise a series of interconnected damper blades driven by an actuator that tilts the blades in unison between open and closed positions. A coupling or linkage that connects the drive actuator to the damper blades can transmit significant torque from the actuator to the blades, thus the blades need to be sufficiently strong to withstand such torque. Increasing a blade's strength and stiffness, however, can increase the blade's cost. Moreover, stronger, thicker blades can increase the damper's airflow resistance and thus reduce its efficiency when fully open.
A second problem pertains to a drive actuator having to drive or tilt the blades both clockwise and counterclockwise to selectively open and close the damper. Reversing the torque direction can involve backlash or play between the actuator and the damper blades, which can cause inaccurate blade positioning. Also, repeated torque reversal can cause fatigue that can weaken various parts of the damper.
Consequently, there is a need for a damper/actuator system that is more efficient, accurate and cost effective.